The vulnerability exists in the Networking: Cache component of Mozilla software and permits an attacker to read cached data that the browser stores during normal use. This can compromise confidentiality by exposing information that may have been cached. The flaw is identified as CWE‑200 – Information Exposure.

Mozilla Firefox and Mozilla Thunderbird are affected. Versions prior to 158 contain the flaw and should be updated to 158 or later.

The CVSS score of 4.3 indicates medium severity, and the EPSS score of <1% suggests a very low probability of exploitation. The issue is not listed in the CISA KEV catalog. Based on the description, it is inferred that the vulnerability appears to require local access or the ability to execute code with the user’s privileges to read the cache; no direct remote exploitation path is documented.